Paxton is best known for his 1972 book Vichy France: Old Guard and New Order, 1940-1944. In opposition to the traditional view pioneered by Robert Aron, he argued that the Vichy government was eager to collaborate with Nazi Germany and did not practice "passive resistance" to German rule. Upon its publication in French translation in 1973, he became the subject of intense vitriol from French historians and commentators; during a televised debate with Paxton in 1976, the Vichy naval leader Gabriel Auphan called him a liar. However, the translation sold thousands of copies, particularly to the young generation shaped by the civil unrest of May 1968 and uninterested in the "cosy mythologies" of Vichy apologists. Today, the book is considered a historical classic and one of the best studies on France in the Vichy era.[1]

In his 1998 paper "The Five Stages of Fascism", he suggests that fascism cannot be defined solely by its ideology, since fascism is a complex political phenomenon rather than a relatively coherent body of doctrine like communism or socialism. Instead, he focuses on fascism's political context and functional development. The article identifies five paradigmatic stages of a fascist movement, although he notes that only Nazi Germany and Fascist Italy have progressed through all five:

Intellectual exploration, where disillusionment with popular democracy manifests itself in discussions of lost national vigor

Rooting, where a fascist movement, aided by political deadlock and polarization, becomes a player on the national stage

Arrival to power, where conservatives seeking to control rising leftist opposition invite the movement to share power

Exercise of power, where the movement and its charismatic leader control the state in balance with state institutions such as the police and traditional elites such as the clergy and business magnates.

Radicalization or entropy, where the state either becomes increasingly radical, as did Nazi Germany, or slips into traditional authoritarian rule, as did Fascist Italy.[4]

In his 2004 book The Anatomy of Fascism, Paxton refines his five-stage model and puts forward the following definition for fascism:

Fascism may be defined as a form of political behavior marked by obsessive preoccupation with community decline, humiliation, or victim-hood and by compensatory cults of unity, energy, and purity, in which a mass-based party of committed nationalistmilitants, working in uneasy but effective collaboration with traditional elites, abandons democraticliberties and pursues with redemptive violence and without ethical or legal restraints goals of internal cleansing and external expansion.[5]